[VIDEO] Subaru Legacy 2.5 with a lot of LAG, as if it had Turbo

[clasik]

My Subaru Legacy 2.5 from 2005 with EJ253 engine and 260,000 km, it has a small and annoying lag when accelerating, if I accelerate slowly the rpm rises correctly, but if I press the pedal hard there is a small step between 700 and 1000 rpm and after half a second enters all the power of the blow. Like the turbocharged engines from the 80s/90s.

I have cleaned the body of the butterfly to discard, but it continues the same.
Video attached.

Can you think of what it could be?

 

[Ecmbuster]

Test the throttle pedal for the correct / smooth voltage and the throttle body voltage / degrees / angle.
The throttle pedal and throttle body should follow each other. Test fuel pressure and ensure the timing belt is correct.

 

[clasik]

Test the throttle pedal for the correct / smooth voltage and the throttle body voltage / degrees / angle.
The throttle pedal and throttle body should follow each other. Test fuel pressure and ensure the timing belt is correct.

I rule out that it is the accelerator pedal sensor, I have been reviewing the graph in the Torque app and there aren't any jump or abnormal reading.

Why do you think that the timing belt can be failing? If it's wrong, it would always be failing.

I will review the fuel pressure.

 

[Ecmbuster]

A 2005 with 260,000 km ... I would check it for wear and stretch and did not mention "failing".....
And the throttle body? did you rule that out? Did you test the MAF for Volumetric efficiency?

Volumetric efficiency - Wikipedia

en.wikipedia.org

EGR sticking? Vacuum leak? Defective PCV?
Your and many other older Subaru models uses the SSM protocol (Subaru Select Monitor) for diagnostics.
Torque is fine for simple testing but doesn't go far enough.

 

[clasik]

@Ecmbuster

A 2005 with 260,000 km ... I would check it for wear and stretch and did not mention "failing".....
And the throttle body? did you rule that out? Did you test the MAF for Volumetric efficiency?

Volumetric efficiency - Wikipedia

en.wikipedia.org

EGR sticking? Vacuum leak? Defective PCV?
Your and many other older Subaru models uses the SSM protocol (Subaru Select Monitor) for diagnostics.
Torque is fine for simple testing but doesn't go far enough.

I cleaned the throttle body and the MAF, I think the throttle body, MAF and throttle pedal are working good because I sped up slowly and the rpm up fine, However I have some suspicions that there are any Vacuum leaks or any problem in the fuel line, fuel pressure regulator for example. Also, I have checked the PCV, It looks fine, it makes good opening and closing sound. I will clean the EGR, but I think it isn't guilty.

I only have an ELM327 and Torque app, I would like to have the SSM however my wallet doesn't allow me.

 

[Ecmbuster]

Free SSM 1.2.5 is PC based and working on older Subaru models without CAN, only K-Line.
Works with XP, Windows 7 and Windows 10. The application will access SSM full Engine and Transmission diagnostics.
Link: https://sourceforge.net/projects/freessm.berlios/files/latest/download
USB Cables used:
VAG-K + CAN USB (at times called KKL or K plus CAN)
OR (FTDI) FT232BL USB
Examples of operation:

Subaru FreeSSM – Complete DIY ECU and TCM Management | AutoInstruct

We show you how to use FreeSSM, a complete DIY tool for ECU and TCM Management of your Subaru vehicle. It provides access to the ECU and TCM for Legacy, Liberty, Outback, Baja, Impreza, Forester and Tribeca models of MY1999 or greater.

www.autoinstruct.com.au

Android Tools used:
JDMscan Application: https://play.google.com/store/apps/details?id=dksoft.jdmscan&gl=US
USB Cables used:
VAG-K + CAN USB
OR (FTDI) FT232BL USB with OTG cable if Android supported

ActiveOBD Application Android

ActiveOBD - Apps on Google Play

Multi function display app for Subaru vehicle MY 2012+ (not official)

play.google.com

Bluetooth OBDLink MX +

ActiveOBD Application iOS version

ActiveOBD

The OBDII scanner app with a special support of Subaru (MY2012+) make. It's the next-generation product based on our well-known "ActiveOBD for Subaru" app bringing its best features to iOS users. A compatible OBD adapter is required. Premium-level adapters supported (best speed and stability)...

apps.apple.com

Requires high quality BlueTooth device such as Bluetooth OBDLink MX +

These tools mentioned are NOT OBD II, these applications are true SSM (Subaru Select Monitor)

I use these tools on these older generation vehicles because they are quick and easy.
With the PC or Android, the screen can be recorded for playback / reference. ie: PC > Camtasia and Android > AZ Recorder

I do this as a Professional Technician and having the latest Snap-On with SSM3 / SSM4 professional tools, they are not cheap.

The USB connections have a much faster refresh rate than BlueTooth but all work perfect for these older models.

 

[clasik]

Free SSM 1.2.5 is PC based and working on older Subaru models without CAN, only K-Line.
Works with XP, Windows 7 and Windows 10. The application will access SSM full Engine and Transmission diagnostics.
Link: https://sourceforge.net/projects/freessm.berlios/files/latest/download
USB Cables used:
VAG-K + CAN USB (at times called KKL or K plus CAN)
OR (FTDI) FT232BL USB
Examples of operation:

Subaru FreeSSM – Complete DIY ECU and TCM Management | AutoInstruct

We show you how to use FreeSSM, a complete DIY tool for ECU and TCM Management of your Subaru vehicle. It provides access to the ECU and TCM for Legacy, Liberty, Outback, Baja, Impreza, Forester and Tribeca models of MY1999 or greater.

www.autoinstruct.com.au

Android Tools used:
JDMscan Application: https://play.google.com/store/apps/details?id=dksoft.jdmscan&gl=US
USB Cables used:
VAG-K + CAN USB
OR (FTDI) FT232BL USB with OTG cable if Android supported

ActiveOBD Application Android

ActiveOBD - Apps on Google Play

Multi function display app for Subaru vehicle MY 2012+ (not official)

play.google.com

Bluetooth OBDLink MX +

ActiveOBD Application iOS version

ActiveOBD

The OBDII scanner app with a special support of Subaru (MY2012+) make. It's the next-generation product based on our well-known "ActiveOBD for Subaru" app bringing its best features to iOS users. A compatible OBD adapter is required. Premium-level adapters supported (best speed and stability)...

apps.apple.com

Requires high quality BlueTooth device such as Bluetooth OBDLink MX +

These tools mentioned are NOT OBD II, these applications are true SSM (Subaru Select Monitor)

I use these tools on these older generation vehicles because they are quick and easy.
With the PC or Android, the screen can be recorded for playback / reference. ie: PC > Camtasia and Android > AZ Recorder

I do this as a Professional Technician and having the latest Snap-On with SSM3 / SSM4 professional tools, they are not cheap.

The USB connections have a much faster refresh rate than BlueTooth but all work perfect for these older models.

Dear @Ecmbuster

At the end, I got a Vag-Com KKL 409.1 cable. I have been analyzing some sensors and metrics, however I can't see any problem here.

I have uploaded two videos, one with every accelerator pedal sensors and metrics, and the other video with others fuel and air flow sensors.

Also, I have attached a zip file with the Romraider logs.

Can you tell me if you see any abnormal metric in this video?, or if you would like to see other sensors or metrics?


Thanks

 

[Ecmbuster]

Throttle Opening Angle (%) is lower than normal but youtube videos are not a repair source unless the vehicle is driven and experienced.
The best measurement with proof is with an oscilloscope to measure the throttle pedal and throttle body.
Measuring the throttle sweep with the tools I suggested and with romraider, should provide a clean stable throttle and throttle body sweep.
Sweep includes the throttle pedal and throttle body with scan tools and oscilloscope.
Known users of romraider have changed / manipulated the engine management system with air/ruel ratio sensors.
Did you test the MAF for Volumetric efficiency as mentioned earlier?

VE Calculator - Apps on Google Play

Volumetric Efficiency Calculator for vehicle driveability. From ATG Training.

play.google.com

 

[clasik]

Throttle Opening Angle (%) is lower than normal but youtube videos are not a repair source unless the vehicle is driven and experienced.
The best measurement with proof is with an oscilloscope to measure the throttle pedal and throttle body.
Measuring the throttle sweep with the tools I suggested and with romraider, should provide a clean stable throttle and throttle body sweep.
Sweep includes the throttle pedal and throttle body with scan tools and oscilloscope.
Known users of romraider have changed / manipulated the engine management system with air/ruel ratio sensors.
Did you test the MAF for Volumetric efficiency as mentioned earlier?

VE Calculator - Apps on Google Play

Volumetric Efficiency Calculator for vehicle driveability. From ATG Training.

play.google.com

I am accelerating in the 1.25 seconds. It seems that is working good, not?
I don't know if this image is enough to discard the MAF. I already cleaned it.

On the other hand, I have some suspicious of Fuel Injection Pressure Regulator, the symptoms fit with FIPR's spring isn't return fast successfully, when I accelerate slowly the rpm rises correctly, but if I press the pedal hard there is a small step between 700 and 1000 rpm and after half a second enters all the power of the blow.

However, I can't found a new FIPR to test in Europe, only in the USA, and it is expensive, neither I have a fuel pressure gauge to confirm the right pressure of fuel pipe.

What do you think?

22670AA390 - Fuel Injection Pressure Regulator - Genuine Subaru Part

Genuine Subaru Part # 22670AA390 - Fuel Injection Pressure Regulator. Fits Forester, Impreza, Legacy, Outback

parts.subaru.com

 

[Ecmbuster]

You have never answered my questions ................................................!
Known users of romraider have changed / manipulated the engine management system with air/fuel ratio sensors.
Was the engine controller tuned?
Were the oxygen sensors replaced with air/fuel ratio sensors?
Did you test the MAF for Volumetric efficiency as mentioned earlier? - That is why an application was added in the post!
Did you measure fuel pressure and fuel flow?
Do you have a repair manual?

 

[clasik]

You have never answered my questions ................................................!
Known users of romraider have changed / manipulated the engine management system with air/fuel ratio sensors.
Was the engine controller tuned?
Were the oxygen sensors replaced with air/fuel ratio sensors?
Did you test the MAF for Volumetric efficiency as mentioned earlier? - That is why an application was added in the post!
Did you measure fuel pressure and fuel flow?
Do you have a repair manual?

Sorry,

Was the engine controller tuned?
Not, It was not

Were the oxygen sensors replaced with air/fuel ratio sensors?
Not, they were not

Did you test the MAF for Volumetric efficiency as mentioned earlier? - That is why an application was added in the post!
Yes, I did.

Did you measure fuel pressure and fuel flow?
Not, I did not have fuel pressure gauge.

Do you have a repair manual?
Yes, I do

 

[Ecmbuster]

Consider your values recorded. Engine Speed (rpm) and Accelerator Pedal Angle (%)
RPM and Accelerator should follow each other. File name "Air fuel ratio.xlsx"
Even with the key ON and engine OFF, the Accelerator Pedal Angle (%) should increase from 0% (closed throttle) to 100% (wide open throttle).
This page should also be followed.
If you did test the MAF for Volumetric efficiency, your values also failed.

 

[clasik]

Consider your values recorded. Engine Speed (rpm) and Accelerator Pedal Angle (%)
RPM and Accelerator should follow each other. File name "Air fuel ratio.xlsx"
Even with the key ON and engine OFF, the Accelerator Pedal Angle (%) should increase from 0% (closed throttle) to 100% (wide open throttle).
This page should also be followed.
If you did test the MAF for Volumetric efficiency, your values also failed.

I managed to fix it by changing the MAF for one from Aliexpress for €17 fixed my car.
Thank you for your help